He also mentioned in a JaME interview that he likes Radiohead. =D However, other than KISS, I'm not sure if he has any influences per say, though if he does, I'd like to know who they are, too. ^^
To further prove the classical music thing, there's the "Yoshiki Selection" CDs. ^^ And he's been playing piano since age 4, so I imagine he probably did grow up listening to at least some classical music. o.o